EP 0 968 371 B1 discloses a fluid cooling device as a structural unit with a drive motor driving a fan wheel and a fluid pump. The fluid pump takes fluid (hydraulic medium) from an oil tank and delivers it to a hydraulic working circuit which heats the fluid, and leads to a heat exchanger from which the fluid returns cooled to the oil tank. In the known solution, the oil tank is made trough-shaped. With its upwardly drawn edges in the manner of a half shell, the oil tank at least partially encloses the motor and the fluid pump. Accordingly, with the known solution the oil tank has a relatively large volume, is still a component of the fluid cooling device in a space-saving compact design, and ensures good accessibility of the motor and fluid pump unit for mounting and maintenance purposes as a result of the installation space left open by the trough edges. In addition to a compact design for the fluid cooling device, the mass components of the cooling device are uniformly distributed, so that in operation a safe upright position is achieved even with the corresponding inherent movements and vibrations.
A control system and process for controlling the speed of a plurality of fans for cooling a plurality of flow agents in a machine are disclosed in DE 100 62 534 A1. The speed of each fan is controlled according to the individual heat dissipation requirements of special heat transfer cores attended by this special fan. This control system has a plurality of sensors positioned to sense the temperature of each of the plurality of flow agents. Each sensor can be operated to output a signal indicating the temperature of this special flow agent. An electronic control device is coupled to a plurality of sensors to receive signals from the sensors which pick up the temperature of each of the plurality of flow agents. Based on these temperature signals, in the known device the electronic control module can determine a corresponding temperature error for each of these flow agents. Based on these temperature error signals and on a certain logic programmed into the electronic control module, the control device outputs a signal to each of the plurality of fans to individually control their speed, each output signal indicating a desired fan speed for this special fan.
With the existing solutions however only one cooling task can ever be performed, i.e., efficient cooling of the heated fluid of a first type, for example, in the form of a hydraulic medium. For other cooling and temperature-control tasks, for example, cooling a fluid of a second hydraulic working circuit (gear oil), the known devices must be provided again so that an independent cooling device with a drive motor, pump, and cooler consequently is required for each hydraulic circuit and each cooling task.